Non-aqueous electrolyte secondary batteries such as lithium ion batteries advantageously have a high energy density, a low self-discharge rate, and good cycle performance. Therefore, in recent years, it has been expected to increase the size or the capacity of the non-aqueous electrolyte secondary batteries to use such secondary batteries as power sources for various types of industrial machinery and equipment. In order to increase the capacity of the non-aqueous electrolyte secondary batteries, it is necessary to increase the number of electrodes to be housed in the non-aqueous electrolyte secondary battery.
It is necessary to electrically connect the electrodes to an electrode terminal. Therefore, if it is attempted to connect the electrodes to an electrode terminal in a non-aqueous electrolyte secondary battery in which an increased number of electrodes are housed, a connection portion of the electrode terminal must be increased in size to secure a region for connection to the electrodes. In addition, a space for connection of a large number of electrodes is necessary around the connection portion of the electrode terminal. If the number of electrodes is increased, further, the resistance at the connection portion between tabs of the large number of electrodes and the electrode terminal is increased. In order to address such issues, Japanese Patent No. 4494731 (Patent Document 1) discloses a secondary battery in which: a plurality of assemblies in which tabs of a plurality of electrodes are welded to an L-shaped current collecting lead (current collecting plate); portions of a plurality of current collecting leads to which the tabs are welded are disposed at intervals to extend in parallel with each other; and base portions of the plurality of current collecting leads are disposed to overlap each other to be bolted and welded to a connection portion of an electrode terminal.